A support group is calling for an independent inquiry into claims that a monk sexually abused girls at a monastery decades ago.

Six women were paid compensation in an out-of-court settlement after alleging they were sexually abused by a monk in the 1970s and 1980s at the monastery on Caldey Island, off the Welsh Coast at Tenby.

Three women came forward with their allegations against Father Thaddeus Kotik, the Guardian reported.

The woman launched civil proceedings against the Cistercian order of monks for personal injuries in August 2016.

The suit claimed Kotik abused six girls between 1972 and 1987 while at the Italianate Abbey of Our Lady and St Samson.

The children's commissioner is set to write to the monastery for assurances that children visiting the island will be safe.

However, the Minister and Clergy Sexual Abuse Survivors groups is calling for an independent investigation.

"In order for that to be open and for all of the facts to be found out, there does need to be an independent inquiry from somebody who is not part of the institution, who can come in with expertise, ask the right questions and find out what happened," said Jo Kind, the group's Welsh representative.

Dyfed-Powys Police said it had investigated the claims against Kotik in 2014 and 2016 but they could not prosecute the monk, who lived on the Pembrokeshire island for 45 years, because he died in 1992.

Kind also requested a "full and frank apology" from the abbot and demanded a law change that made reporting sexual abuse mandatory. "That would make it much easter for people to report because victims wouldn't fear that it would damage their relationship with the institution," Kind said.

"There would have been a lot of people who knew about Father Thaddeus, not just on the island but further up the Cistercian order.

"The people that have been abused in this way deserve an independent inquiry so the truth of what happened is fully exposed. They need to know who knew what and when."

Court documents show several victims reported the alleged sexual abuse to school officials and the then-abbot. However, nothing was done.

One of the victims also wrote a letter to current abbot, Brother Daniel van Santvoort, who acknowledged Kotik's abuse and said he had previously heard allegations against Kotik. The abbey later argued it was unaware of the abuse.

Children's Commissioner for Wales Sally Holland said there was "not enough information available" to launch an investigation, the BBC reported.

"I have written to the Abbey on Caldey Island for more information on their child protection procedures to make sure that any child or young person visiting Caldey or its churches is safe," she said.

Kotik is said to have befriended family who visited the island and then sexually abuse their children, according to court papers.